redbruce
Eats Squid
HDPE is impervious to moisture.yep, assuming lid has sealed, 120ml sram dot container half empty, 20c degree air at 100% RH occupied the empty void of the bottle, a cubic meter of air can hold 17.3 grams of h2o at 20c, so 60cc of air can hold 0.001038 grams of h2o, thats going to be 0.0000173% of the fluids volume is h2o in your bottle
unknown, is the bottle actually a perfect seal, through the HDPE bottle itself or the cap seal. I suspect not.
this is where we need our resident chemist, REDBRUCE!!!!!
We store samples in it in fridge (very low RH) for months, even years with no contents loss/gain. Cap seal is weak link.
The only source of moisture will be in the air above the fluid. In Melbourne RH in summer is typically 40-50% (but last sat morning was 75%RH @24 degree after rain night before) and 50-70% in Winter so 100% would definitely be worst case here.
In any case the moisture in the air will eventually be partitioned between the liquid and vapour phase (not sure what the partition co-efficient is) so the amount of water in the fluid will be less than 0.001038 g in the 60ml.
2% moisture in DOT fluid is considered the point at which boiling point for MTB braking applications is critical so the amount of moisture in a left over half bottle is miniscule.
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